[Heterogeneity of neural muscular atrophies]

Classification of the hereditary motor and sensory neuropathies is discussed and findings reported in the recent literature are compared to our own findings in a kinship with autosomal dominant CMT. Previous studies in CMT-families with comparable slow nerve conduction velocities had shown positive linkage of this hereditary neuropathy to the Duffy blood group locus; however, blood group typing in the recently studied kinship excluded close linkage, which may indicate the existence of another sub-group in this entity. Testing of visually evoked potentials in this kindred demonstrated significant differences in P 100 latencies of the families of twin brothers. This intrafamilial difference may also be an expression of heterogeneity.